3 research outputs found
3D-Printed Paper Spray Ionization Cartridge with Fast Wetting and Continuous Solvent Supply Features
We
report the development of a 3D-printed cartridge for paper spray
ionization (PSI) that can be used almost immediately after solvent
introduction in a dedicated reservoir and allows prolonged spray generation
from a paper tip. The fast wetting feature described in this work
is based on capillary action through paper and movement of fluid between
paper and the cartridge material (polylactic acid, PLA). The influence
of solvent composition, PLA conditioning of the cartridge with isopropanol,
and solvent volume introduced into the reservoir have been investigated
with relation to wetting time and the amount of solvent consumed for
wetting. Spray has been demonstrated with this cartridge for tens
of minutes, without any external pumping. It is shown that fast wetting
and spray generation can easily be achieved using a number of solvent
mixtures commonly used for PSI. The PSI cartridge was applied to the
analysis of lidocaine from a paper tip using different solvent mixtures,
and to the analysis of lidocaine from a serum sample. Finally, a demonstration
of online paper chromatography–mass spectrometry is given
Fused Deposition Modeling 3D Printing for (Bio)analytical Device Fabrication: Procedures, Materials, and Applications
In
this work, the use of fused deposition modeling (FDM) in a (bio)analytical/lab-on-a-chip
research laboratory is described. First, the specifications of this
3D printing method that are important for the fabrication of (micro)devices
were characterized for a benchtop FDM 3D printer. These include resolution,
surface roughness, leakage, transparency, material deformation, and
the possibilities for integration of other materials. Next, the autofluorescence,
solvent compatibility, and biocompatibility of 12 representative FDM
materials were tested and evaluated. Finally, we demonstrate the feasibility
of FDM in a number of important applications. In particular, we consider
the fabrication of fluidic channels, masters for polymer replication,
and tools for the production of paper microfluidic devices. This work
thus provides a guideline for (i) the use of FDM technology by addressing
its possibilities and current limitations, (ii) material selection
for FDM, based on solvent compatibility and biocompatibility, and
(iii) application of FDM technology to (bio)analytical research by
demonstrating a broad range of illustrative examples
Comparison of Biocompatibility and Adsorption Properties of Different Plastics for Advanced Microfluidic Cell and Tissue Culture Models
Microfluidic technology is providing new routes toward
advanced
cell and tissue culture models to better understand human biology
and disease. Many advanced devices have been made from poly(dimethylsiloxane)
(PDMS) to enable experiments, for example, to study drug metabolism
by use of precision-cut liver slices, that are not possible with conventional
systems. However, PDMS, a silicone rubber material, is very hydrophobic
and tends to exhibit significant adsorption and absorption of hydrophobic
drugs and their metabolites. Although glass could be used as an alternative,
thermoplastics are better from a cost and fabrication perspective.
Thermoplastic polymers (plastics) allow easy surface treatment and
are generally transparent and biocompatible. This study focuses on
the fabrication of biocompatible microfluidic devices with low adsorption
properties from the thermoplastics poly(methyl methacrylate) (PMMA),
polystyrene (PS), polycarbonate (PC), and cyclic olefin copolymer
(COC) as alternatives for PDMS devices. Thermoplastic surfaces were
oxidized using UV-generated ozone or oxygen plasma to reduce adsorption
of hydrophobic compounds. Surface hydrophilicity was assessed over
4 weeks by measuring the contact angle of water on the surface. The
adsorption of 7-ethoxycoumarin, testosterone, and their metabolites
was also determined after UV-ozone treatment. Biocompatibility was
assessed by culturing human hepatoma (HepG2) cells on treated surfaces.
Comparison of the adsorption properties and biocompatibility of devices
in different plastics revealed that only UV-ozone-treated PC and COC
devices satisfied both criteria. This paper lays an important foundation
that will help researchers make informed decisions with respect to
the materials they select for microfluidic cell-based culture experiments